Evaporator



M. J. KERMER Oct. 1, 1935.

EVAPORATOR Filed May 5, 1934 2 Sheets-Sheet 1 INVENTQR 173a ATTORNEYS Patented Oct. 1, 1935 UNITED STATES PATENT OFFICE Buffalo Foundry & Machine 00.,

, Buffalo,

N. Y., a corporation of New York Application May 3, 1934, Serial No. 723,739

5 Claims.

This invention relates to an evaporator of the type in which vaporization is effected by heat in order to concentrate the liquor and increase the proportion of the solid or dry content relative to the liquid content of the same.

In evaporators of this character, as heretofore constructed for concentrating liquors containing solids, the liquor entrained in the vapors discharged from the apparatus may contain an appreciable amount of these solids.

In the case of very valuable solids the discharge of a vapor mixture containing a small amount of such solids involves a substantial loss when operating an apparatus of the character heretofore in use.

It is therefore the object of this invention to provide an evaporator which enables a greater amount of solids to be recovered from a liquor and thus efiects a substantial economy.

To that end this invention consists generally in passing the vapor mixture in which solids-laden liquor is entrained through an aqueous scrubbing medium, whereby solids and liquids are separated more completely from the vapors and the latter are discharged practically free from valuable j solids, thereby avoiding the waste which has occurred heretofore, and rendering the loss of solids practically negligible.

In the accompanyingdrawings:

Figure 1 is a vertical section of one form of apparatus embodying my invention.

Figure 2 is a horizontal section of the same taken on line 2-2 Fig. l. v

Figure 3 is a vertical section showing another form of my invention.

Figure 4 is a vertical transverse section taken on line 4-4 Fig. 3.

In the following description simil ar characters of reference indicate like parts in the several figures of the drawings.

Referring to the construction of the apparatus shown in Figs. 1 and 2, the numeral I represents in general a heater or heating element which may be of any suitable or approved construction for the purpose of heating the liquor which is to be evaporated or concentrated, for the purpose of vaporizing the same and ultimately'increasing the proportion of solid content in the solution. The

particular form of heater for this purpose which is shown in the drawings comprises a bundle or cluster of heatingtubes or conduits 2, a lower 'liquid inlet chamber 3 which communicates with/ the lower ends of these tubes and from which the liquor to be concentrated is supplied to the lower ends of these heating tubes, an upper vapor out- 1 let chamber 4 which communicates with the upper ends of the heating tubes and which receive the vapor mixture therefrom as the result of heating the liquor in these tubes, and a shell or casing 5 enclosing the bundle or cluster of heating tubes and forming a heating chamber or jacket around the same. A heating agent is supplied to this last-mentioned chamber and is adapted to operate upon the exterior of the heating tubes for the purpose of heating the liquor which passes upwardly through the interior thereof. Although any suitable heating agent ,may be employed it is preferable to employ steam for this purpose which is introduced by means of a pipe 6 into the upper part of the heating chamber while the water of condensation is withdrawn from the lower end of this chamber by means of a pipe 1. The liquor to be heated is introduced into the liquor inlet chamber through an inlet 8 in the same, which inlet is connected with a pipe 9 through which raw liquor may be supplied to this inlet chamber from any suitable source, and the amount thus supplied regulated by means of a valve II] in this pipe. This inlet 8 is also connected with a return pipe I l which conducts previously heated and partially concentrated liquor back to the inlet chamber 3 for the purpose of re-circulating the same and further concentrating it.

The numeral l2 represents, in general, a separator whereby a large part of the liquor entrained in the vapor mixture issuing from the vapor outlet chamber 4 of the heater are separated preparatory to re-heating this liquor and also operating upon the separated vapor mixture for the purpose of recovering solids or dry material which may be entrained therein. This separator preferably comprises an upright cylindrical body l3 provided with a lower downwardly tapering conical end l4 communicating with the return pipe 4 ll. Between its upper and lower ends this separator body is provided with a vapor inlet l5 which is connected by means of a conduit I6 withthe outlet ll of the vapor chamber 4 of the heater.

After the vapor mixture passes from the upper ends of the heating tubes 2 into the vapor chamber 4 this mixture is conducted by the conduit l6 into the body of the separator where the greater part of the liquor contained in this mixture is separated therefrom and drops to the bottom thereof, so that this liquor may be re-co'nducted through the return pipe H and inlet 8 into the liquor supply chamber 3, preparatory to again-passing upwardly through the heating tubes for repeating the vaporization operation.

While liquor is being returned from the separator to the heater in the manner described additional raw liquor may be supplied through the pipe 9 in such quantities as may be required by adjusting the valve I0 accordingly.

The vapor mixture separated from the liquor in the separator body l3 passes upwardly from the open upper end of the separator body and into the scrubbing chamber l8 which preferably comprises an upright cylindrical body I9, a closed top 20, and a bottom 2|. The upper portion 22 of the body l3 of the separator projects upwardly through the central part of the bottom 2| of the scrubbing chamber and terminates a considerable distance above this bottom so as to form an annular scrubbing tank 23 above this bottom and between the periphery of the upper part of the separator wall and the lower part of the upright wall of the scrubbing chamber. A vacuum is produced in this scrubbing chamber, the separator and the heater communicating therewith so as to withdraw the vapor mixture through an exhaust pipe 24 which communicates at its upper end with a vapor outlet 26 on the upper part of the scrubbing chamber while its opposite end may be connected with an exhausting device of any suitable character such as a barometric condenser, an exhausting pump, or another effect of a multiple evaporator in a manner well-known in this type of apparatus.

As the vapor mixture issues from the upper end of the separator body I3 and passestoward the outlet 25 of the scrubbing chamber this mixture is acted upon by means which operate to scrub this mixture and separate therefrom the greater part, if not all, of the solids bearing liquids which may be entrained in the vapors.

The particular form of the scrubbing means for this purpose shown in Figs. 1 and 2 are constructed as follows:

The numeral 26 represents a pipe'forsupplying hot water to the tank 23 so that hot water will always be present in this tank of a suflicient depth to permit of passing the vapor mixture from the separator through this water and remove liquid from this mixture together with solids contained in the same. The heated liquid thus supplied to the scrubbing tank preferably consists of the condensate which is discharged from the lower end of the heater jacket through the pipe I, which latter is connected with the inlet of a pump 30. The outlet of the latter is connected with the water supply pipe 26 and also with a waste pipe 28 containing a valve 29. Only a very small part of the water of condensation is carried from thepump 30 through the pipe 26 to the scrubbing tank 23, the remainder being discharged through the waste pipe 28, the division of this water being regulated by the respective valves 21 and 29 in these pipes to best suit any particular requirements.

Inasmuch as the heat of the water transferred from the jacket of the heating element is always greater than the heat in the separator and scrubbing chamber, no condensation of vapors occurs in the apparatus. As an example, the temperature of water transferred from the heating element to the scrubbing tank may be 150 F. while the temperature of the vapor mixture passing from the separator to the tank 23 may be F. and the vacuum may be 27 inches.

The level of the liquid in the scrubbing tank is always maintained the same by means which pref erably operate automatically and which in the present case comprise a trap chamber 3| having its lower end connected by a conduit 32 with the lower end of the scrubbing tank 23, a pressure balancing pipe 33 connecting the upper part of the trap chamber with the upper part of the scrubbing chamber, and an overflow pipe 34 communicating at its upper end with the trap cham- 5 her above the lower inlet 32, while the lower end of this overflow pipe communicates with the spaces or conduits leading to the liquid inlet chamber 3 of the heater. This is accomplished in the instant case by connecting the lower end of 10 the pipe 34 with the lower part of the separator chamber or body I3, as shown in Fig. 1.

When the water or scrubbing liquid supplied by the pipe 26 has risen in the scrubbing chamber and trap chamber up to the point of connection between the overflow pipe 34 and the trap chamber, then any further introduction of water into the tank will cause a corresponding amount of water t.) escape through the overflow pipe 34 and return to the separator for recirculation in 20 the apparatus, thereby maintaining the scrubbing water in the tank 23 always at the same level.

For the purpose of enabling the level of the scrubbing liquid in the tank to be regulated to suit the character of the solution which is being evaporated and to meet other varying conditions, I the liquid outlet of the trap chamber is made vertically adjustable. Satisfactory means for ac- 'may be held in position after adjustment by various means, for example by bolts 3|2 mounted on a the trap chamber and passing through vertical slots on the adjusting plate. 40

In order to insure uniformity in the character of the scrubbing water in the tank, means are provided for compelling the water to circumferentially traverse the entire tank from the time it enters the tank to the time it leaves the same. 5 This is preferably accomplished by arranging the connection between the tank and the trap chamber and scrubbing water supply pipe 26 close together on one side of the scrubbing tank and placing an upright radial partition23l'across 50 that part of the annular tank between the trap chamber and overflow pipe, as shown in Figs. 1 and 2.

By this means water enters the tank through the pipe 26 and is compelled to make nearly a 55 complete circle before it can escape through the trap chamber, thus ensuring a uniform distribution of the scrubbing water for more effectively removing therefrom liquors entrained in vapor mixture. 60

Within the scrubbing chamber and above the upper end of the separator body is arranged a lower bell-shaped bafile which comprises a baffle head 35 extending over the outlet of the separator body, and an annular baflie flange 36 extend- 65 ing from the edge of this head downwardly into the annular scrubbing tank about midway between the separator body and the wall of the scrubbing chamber, this flange being of such height that its lower end dips into the water or liquid within the scrubbing tank. This water or liquid thus forms a seal or bath between the upper end of the separator and the scrubbing chamber through which the vapor mixture issu- 75 ing from the separator is first compelled to pass downwardly through the inner part of the scrubbing bath, thence outwardly around the lower edge of the bell flange 36 and thence upwardly through the outer part of this bath before proceeding further. During this operation a considerable part of the solids or dry substance bearing liquids entrained in the vapors are separated therefrom and retained in the bath. This bell-shaped baffle may be supported in any suitable manner, for example by means of upright posts 3'! secured at their lower ends to the upper end of the separator body and connected attheir upper ends with the head of this baifle, as shown in Fig. 1.

An intermediate baffle ring 38 of upwardly tapering or dished form the lower bafile within the scrubbing chamber, which baffle ring rests with its peripheral edge on a shoulder 39 provided on the inner side of the wall of the scrubbing chamber so that this-baille ring is spaced apart from the head of the bellshaped lower baffle to form a horizontal radial passage therebetween which extends from the upper end of the annular space between the lower bafile and the scrubber body to the opening 4i formed centrally in the bafile ring above the head of the lower bafile, as shown in Fig. 1. The vapors rising from the outer part of the water in the tank pass upwardly between the wall of the scrubbing chamber and the flange of the bell-shaped baffie, thence inwardly through the radial space between the head of the bellshaped baflle and the intermediate baffle ring, and during this movement these vapors engage with the adjacent surfaces of the bafile bell, scrubber wall and baffle ring, and additional liquid entrained in the vapors is deposited on these surfaces and then flows therefrom into the liquid of the scrubbing tank.

Within the scrubbing chamber and above the central opening 4| in the ring baflle is arranged an upper bafile disk 42 which is preferably of upwardly dished form and overhangs the inner edge of the intermediate bafile ring 34 and is supported in this position by means of posts 43 secured at their lower and upper ends to the upper side of the intermediate ring baflle and the marginal part of the upper disk baffle 42. This upper baliie is spaced apart from theintermediate bafile so as to form a radial passage therebetween, whereby the vapors issuing from the central opening 4| in the intermediate baffie will be compelled to pass laterally outwardly between the upper and intermediate baflle members, and thence upwardly into the upper part of the scrubber chamber. From the latterthe vapors pass through the outlet 25 to the following effect of a multiple effect evaporator .or to the exhausting device.

Any liquid deposited on the upper side of the upper bafile 42 will flow to the outer edge of the same and then drop therefrom onto the upper side of the intermediate baflle where it joins any liquid deposited on the last-mentioned surface and then flows to the marginal part of the intermediate baflle and drops through an opening 44 in the margin of the intermediate baflle into the bath of liquid in the scrubbing or trough 45 is provided on this bafiie which catches this liquid and conducts the same to an is arranged above opening 46 therein. If desired the liquid gathered in the channel 45 -iay be dropped directly from the hole 46 to the top of the intermediate baflle 38, but it is preferable to employ an upright tube 41 which is connected at its upper end with this opening and terminates at its lower end adjacent to the upper side of the intermediate bafile so that the liquid received by the channel 45 will be deposited on the intermediate bafile without any appreciable splashing and thereby 10 avoid re-entrainment of the liquid thus separated in the vapor passing laterally outward between the intermediate and upper baffles.

On its inner edge the intermediate baflle is provided with a doi iwardly opening annular 15 channel or trough 48 which is adapted to catch any liquid deposited on the underside of the intermediate baflle and cause the same to flow laterally thereon toward the wall of the scrubbing chamber and thus prevent the vapors while 20 flowing around the inner edge of the intermediate bafile from carrying any liquid from this edge and re-entraining the same inthe vapors.

From the foregoing it will be apparent that vapor mixture discharged from the separator is 25 subjected to a thorough strippingaction by the scrubbing bath which is traversed by this mixture and the deflecting effect on the same which is produced by the bafiles forming the tortuous passage in the scrubbing chamber, and that the 30 vapors are thus deprived of the concentrated liquid containing the solids which are the objective of this prpcess. The amount of solids in any particular quantity of water is relatively small but the recovery of the same is desirable and 35 profitable, particularly when the solids or dry substances are very valuable.

As the stream of vapor mixture flows continuously through the scrubbing bath and the solids bearing water released from the vapors and de- 40 posited on the baflle member are discharged into the scrubbing bath, the latter becomes charged with solids. The bath thus charged with solids flows out of the scrubbing tank through the outlet 3 of the trap chamber, due to the inflow of 45 water through the pipe 26, whereby the solids bearing water is returned to the heater through the medium of the conduit of which the lower part of the separator body and the return pipe I I form a part. Inasmuch as the solids-laden liquid 50 is repeatedly circulated through the heater, separator and scrubber in this manner, the evaporated or concentrated liquid ultimatelyv contains the major amount of recoverable solids.

The concentrated solution may be withdrawn 55 from the apparatus in any suitable manner, for example, through a discharge pipe |3l connected with the lower part of the separator chamber l3 and containing a valve I32, as shown in Fig. 1. Draining of the apparatus may be effected 50 through a wash-out pipe 19 connected with the bottom of the heater inlet chamber 3 and containing a valve 80.

In the form of apparatus embodying my invention shownin Figs. 3 and 4, the heater and sepa- 5 rator are of substantially the same construction as that shown in Figs. 1 and 2, but the scrubbing mechanism shown in the first-mentioned figures is varied somewhat and constructed as follows:-

The numeral represents a scrubbing chamber having a horizontal wall or body 82 and upright heads 83, 84 at its front and rear ends. In its front head this scrubbing chamber is provided with a central inlet Illll for the vapor mixture which is conducted to the same by a pipe 85 from 75 the upper end of the separator chamber 86, and in its rear head the scrubbing chamber is provided with a vapor outlet 81 which is connected by a pipe 88 with the inlet of another efiect forming part of a multiple effect evaporator, or a barometric condenser, a pump or other exhausting device for the purpose of creating a vacuum in the scrubbing chamber, separator and heater I which are in communication with each other in the manner shown in Figs. 1, 2, 3, and 4.

Within the front part of the horizontal scrubbing chamber is arranged a central spreading baffle 89 which may be supported on the wall of the horizontal scrubbing chamber by braces 90, as shown or by other suitable means, and which preferably has a forwardly tapering front end SI and a rearwardly tapering rear end 92. Centrally within the scrubbing chamber 8| and in rear of the central spreading bafile is arranged a nozzle 93 of any suitable construction which is adapted to deliver forwardly a conical spray of heated scrubbing water so that this spray forms a water screen extending across the annular space or passage between the central spreading baffle and the wall of the horizontal scrubbing chamber.

Scrubbing water is supplied to this nozzle by a pipe 94 containing a regulating valve 95 and connected with the outlet of a pump 98 having its inlet connected with the lower end of the jacket 5 of the liquor heater so that the heated water of condensation can be withdrawn'from the latter in the same manner in which this is done in the construction shown in Fig. 1. Whatever water is not required for producing a. spray at the nozzle is discharged from the outletof the pump 98 through a waste pipe 96 containing a valve 91.

Within the rear part of the horizontal scrubbing chamber, baflie means are provided which compel the vapors to take a tortuous or serpentine course in passing through this part of this chamber to the vapor outlet 81, which baffle means preferably consist of a plurality of upright baffle plates 99, 99I, 992 arranged in a longitudinal row and projecting alternately downwardly from the top and upwardly from the bottom of the wall of this chamber.

As the vapor mixture passes rearwardly in the scrubbing chamber from the vapor mixture inlet in its front end toward the vapor outlet in the rear end thereof, this mixture is spread by the conical center baffle into an annular stream which traverses the annular screen or curtain of the continuously flowing water spray issuing from the nozzle 93, whereby liquid entrained in the vapor together with the solids carried in this liquid are removed from the vapors, said solids bearing liquid and scrubbing water together dropping on to the bottom of the horizontal scrubbing chamber. In its further course through the rear part of the horizontal scrubbing chamber the same is intercepted and successively diverted by the vertical baffle plates which compel the vapors to take a serpentine or tortuous course through this chamber and cause liquid and solids entrained in the vapor mixture to be deposited on the front sides of these plates. Any water and solids deposited on these plates drop from the latter to the bottom of the respective scrubbing chamber.

The solids-laden liquid recovered by the scrubbing action of the water spray and that 'flowing from the baiiie plates travels along the bottom of the scrubbing chamber 8ll to a sump I02, an opening l| being provided between the bottom of this chamber and the lower baiiie plate 99! to permit such flow. From the sump the solids laden liquid is conducted to the inlet end of the heater, or heating element, which is preferably accomplished by connecting the bottom of the sum by a pipe I03 with the lower part of the separator chamber 86, as shown in Fig. 3.

The water containing the recovered solids or dry substances is thus returned to the evaporator for further concentration.

Each of the baffle plates 99, 9!, 992 is provided at its free inner edge with a forwardly projecting channel, gutter or trough 993 which is adapted to catch any liquid which may be deposited against the front side of the respective baffle plate and prevent the stream of vapors while sweeping around the inner edges of these plates from carrying away such liquid and re-entraining the same in the vapor.

The channel of each upper depending bafile plate preferably inclines laterally, as shown in Fig. 4, and is provided at its lowermost part adjacent to the side wall of the wall 82 with an opening 994 through which liquid caught by the respective channel is discharged adjacent to this wall so that the same is not liable to be re-en- 5 trained.

The channel 993 at the upper end of the lower bafile plate 991 is not provided with an opening similar to that in the channels on the upper baflle plates 99, 992, nor need it be inclined inasmuch as it serves to catch liquid deposited on the front side of the lower plate and compels the same to flow downwardly on this plate instead of being carried away by vapors passing around the upper edge of the lower plate and re-entrained in the vapors The economy effected by the use of this apparatus may be illustrated by the following examples:

Let it be assumed that we are evaporating a liquor which is a 50 per cent solution so as to produce 4,000 pounds of vapor mixture per hour according to the methods heretofore in use, and that the quality of this vapor mixture is 99.9 per cent pure, and 0.1 per cent entrained solution, that is to say, this liquor when ordinarily evaporated yields 3,996 pounds of pure vapor and 4 pounds of solution. Being a per cent solution the same contains 2 pounds of dry substance or solids and 2 pounds of water, so that 48 pounds 50 of dry substance would be lost during 24 hours of operation if no means were provided for saving any of the same. 4

For comparison it will be assumed that a 50 per cent solution is to be evaporated, that when 'the apparatus shown in Figs. 1 and 2 is fully in operation 4,000 pounds of liquid will be evaporated, there will be l,500 pounds of water constantly present in the tank 23, that water is added to and subtracted from the tank at the rate of 50 pounds per hour so that 2,700 pounds of water will be used for scrubbing the vapor mixture which is discharged from the separator during 24 hours, that a vacuum of approximately 27 inches is maintained in the apparatus, that the water transferred from the jacket of the heater to the tank 23 has a temperature of approximately 150 degrees F., and that the vapor mixture issuing from the separator has a temperature of approximately 115 F.

The addition of 48 pounds of dry substance to the 2,700 pounds of scrubbing water in the tank makes a total of 2,748 pounds of solution. Inasmuch as the vapor mixture coming into the scrubbing chamber l8 at the rate of 4,000 pounds per hour still has a quality of 3,996 pounds of pure vapor and 4 pounds of solution, this vapor mixture when operated on in this apparatus in the manner described will yield a solution containing 1.75% of solids or dry substance. Therefore the 4 pounds of solution contained in the vapor produced each hour contains 1.75% solids which is equal to 0.07 pounds of solids per hour. Therefore in 24 hours the loss would amount to 1.68 pounds.

It will thus be noted that this loss as compared with a loss of 48 pounds of dry substance in other methods effects a saving of 46.32 pounds of dry substance per day.

Operation of this apparatus for a'year of 300 working days would therefore effect a saving of 13,896 pounds of dry substance which materially reduces the cost of a product procured by the use of this apparatus.

The operation of the apparatus shown in Figs. 3

and 4 is substantially the same as that described with reference to Figs. 1 and .2, the only difference being that in Figs. 3 and 4 the vapor mixture passes through the scrubbing water in the form of a spray instead of in the form of a bath.

It will therefore be noted that by the use of this apparatus in the manner described, the loss of solids is practically negligible which is very important when recovering solids which are very valuable.

I claim as my invention:-

1. An evaporator comprising a heating element adapted to be heated by steam and to vaporize liquor, a separator receiving vapors from said heating element and adapted to separate liquid entrained therein, means for returning liquid from the separator to said heating element, a tank which receives water of condensation from said heating element for forming a scrubbing bath, means for conducting vapor mixture from said evaporator through said bath, means for conducting liquid from said tank to the liquor inlet of said heating element, and means for withdrawing vapor from said tank.

2. An evaporator comprising a heating element for vaporizing liquor, a separator receiving vapors from said heating element and adapted to separate liquid entrained therein, a tank which receives heated water for forming a scrubbing bath, means for conducting vapor mixture from said separator through said bath, a trap chamber connected at its lower end with said tank and having an outlet above its lower end, and a supporting plate extending over said outlet and adjustable vertically on said trap chamber and having an overflow conduit communicating with said outlet.

3. An evaporator comprising a heater having an inlet for-liquor, an outlet for vapors, liquor conduits communicating with said inlet and outlet, and means for applying heat to said conduits for heating the liquor; a separator having a vapor inlet communicating with the vapor outlet of said heater, a liquor outlet communicating with the inlet of said conduits, and a vapor mixture outlet; a scrubbing chamber having a vapor mixture inlet communicating with the vapor mixture outlet of said separator and also having a vapor outlet adapted to communicate with an exhausting device; and scrubbing means for removing solids bearing liquid from the vapor mixture issuing from the vapor outlet of said separator including the upper part of said separator extending into the lower part of said scrubbing chamber and forming an annular scrubbing tank between the lower part of said scrubbing chamber and the upper part of said separator and adapted to receive a scrubbing liquid; and bafile means arranged in said scrubbing chamber and adapted to cause the vapor mixture passing from the outlet of said separator toward the outlet of said scrubbing chamber to traverse the liquid in said tank, including a lower bell-shaped member having a head arranged over the outlet of said separator and an annular flange projecting downwardly from'said head into the scrubbing liquid in=said tank, an intermediate ring projecting from the side of said scrubbing chamber inwardly over said head, and an upper disk arranged above said ring and projecting laterally beyond the inneredge of the same.

4. An evaporator comprising a heater having an inlet forliquor, anoutlet for vapors, liquor conduits communicating with said inlet and outlet, and means for applying heat to said conduits for heating the liquor; a separator having a vapor inlet communicating with the vapor outlet of said heater, a liquor outlet communicating with the inlet of said conduits and a vapor mixture outlet; a scrubbing chamber having a vapor mixture inlet communicating with the vapor mixture outlet of said separator and also having a vapor outlet adapted to communicate with an exhausting device; and scrubbing means for removing solids bearing liquid from the vapor mixture issuing from the vapor outlet of said separator including a bafile arranged centrally in said scrubbing chamber opposite the vapor mixture inlet thereof and forming an annular passage between said bafile and the wallof said chamber, a nozzle adapted to deliver a spray of scrubbing liquid across said annular passage for recovering solids bearing liquid contained in said vapor mixture, and bafile plates arranged in said scrubbing chamber between said nozzle and the vapor outlet of said scrubbing chamber and projecting alternately upwardly and downwardly from the wall of said scrubbing chamber; and a sump communicating with the lower part of said scrubbing chamber to receive liquid therefrom and communicating with the inlet of said heater for returning the liquid to the latter.

5. The hereindescribed method of evaporating liquor comprising heating the liquor, subjecting the vapor mixture resulting from said heating operation to a primary separating operation so' as to effect an initial separation of solids bearing liquid from' such vapor mixture, reheating said initially separated solids bearing liquid, subjecting the vapor mixture issuing from said primary.

separating operation to a scrubbing operation by passing the same through a s qubbing liquid and further removing solids bearing liquid therefrom, and subjecting said scrubbing liquid to another heating, separating and scrubbing operation.

MARTIN J. KERMER. 

